Custom Runtime for Stackless Python

I feel a pain to use Stackless Python (custom runtime) with Chalice.
I think 'aws lambda create-function --runtime provided' option equivalent in config.json will be good for Stackless Python. 'bootstrap' and the interpreter will be placed on 'vendor' directory.

Start by tracing how config.json represents the Lambda runtime and how deployment packages the vendor directory. Compare the requested provided runtime behavior with the aws lambda create-function --runtime provided option; done means Stackless Python can be configured and the bootstrap and interpreter are placed in vendor.

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